The present invention relates generally to electrical connectors, and more specifically to a new and improved snap-in connector for electrical junction boxes and the like.
Snap-in connectors have been used to connect flexible metallic conduit and metal clad cable to electrical junction boxes. These connectors are an improvement over the prior use of lock nuts that are threaded on the end of an electrical fitting extending through a hole into the interior of the box.
U.S. Pat. No. 5,171,164, dated Dec. 15, 1992, discloses a snap-in connector consisting of a zinc die cast fitting that carries a spring steel adaptor ring designed to secure the fitting to a junction box. The split ring spring steel adaptor is formed with three radially outwardly bent locking tabs and three radially outwardly bent tensioning fingers. In use, the end of the zinc die cast fitting carrying the spring steel adaptor is pushed through an opening in the junction box until the locking tabs clear the edge of the opening and spring outwardly against the inner wall surface of the box, thereby preventing the fitting from being withdrawn. The tensioning fingers press against the edge of the opening to exert tension between the spring steel adaptor and the inner circumference of the opening in the box.
As disclosed in U.S. Pat. No. 5,171,164, the spring steel adaptor ring requires separate manufacturing and assembly operations. A stamping is made with the outwardly bent tabs and fingers. The stamping is then bent into a split ring which must assembled onto the zinc die cast fitting.
An object of the present invention is to provide a quick connect fitting for an electrical junction box consisting of a one-piece, zinc die cast fitting having the snap-in capability described in U.S. Pat. No. 5,171,164 without requiring a separately formed, split ring spring steel adaptor.
The invention is based on the discovery that it is possible to make a one-piece, zinc die cast fitting with flexible locking fingers or tabs and tensioning fingers by locating the locking fingers 180xc2x0 apart and forming the tensioning fingers adjacent to and on either side of each locking finger. The one-piece construction of the invention eliminates the need for making a split ring steel adaptor in manufacturing operations separate from the zinc die casting and then assembling the ring onto the die cast fitting.
In a preferred and disclosed embodiment, the snap-in connector of this invention is a one-piece die cast member having a cylindrical end portion, an outer radial collar, two locking fingers or tabs spaced 180xc2x0 apart that spread outwardly from the cylindrical end portion toward the collar, the locking fingers having free ends that are spaced from the collar and can be flexed radially inwardly, and tensioning fingers formed in the cylindrical leading end portion adjacent to and on each side of the locking fingers. The tensioning fingers spread outwardly from the leading end portion toward the collar and have free ends that can be flexed radially inwardly. In use, the locking and tensioning fingers are flexed radially inwardly by inserting the leading end portion of the die cast fitting through an opening in the wall of a junction box until the free ends of the locking fingers are completely through the opening end and flex outwardly to engage the inside wall surface of the box, thereby preventing the fitting from being withdrawn. The free ends of the tensioning fingers remain engaged with the edge of the box opening in order to center and form a firm connection between the fitting and the box.
Because of the placement of the locking and tensioning fingers, it is possible to form the fingers as integral parts of the zinc die casting. Even though they are an integral part of the die casting, the fingers have the flexibility necessary to provide a secure snap-in connection. Thus, the construction eliminates the need for a separately formed spring steel adaptor that heretofore has been considered necessary to achieve a snap-in connection.
Other advantages and a fuller understanding of the invention will be apparent to those skilled in the art from the following detailed description and the accompanying drawings.